As more and more uses are found for computers, and as existing uses are augmented and improved, it is often necessary to provide increasing amounts of input to computers. Numerous input mechanisms already exist, and additional mechanisms continue to be developed. For many purposes, however, the computer keyboard remains the primary computer input device. As such, there are numerous possible advantages to increasing the amount of data that a user can input to a computer via a keyboard. As used herein, “keyboard” includes, but is not limited to, “QWERTY” computer keyboards as described by, e.g., International Standard ISO/IEC 9995-1.
One manner of increasing the data which a keyboard can input is by increasing the number of keys. For example, many keyboards contain standard function keys (e.g., F1, F2, etc.). Some keyboards have application-specific keys in addition to the common character and function keys; examples include a separate key which a user presses to connect to the Internet, etc. There are practical limits on the number of keys that can be added, however. If the keys become too numerous, some of the keys may be difficult to reach, and users may have difficulty remembering the purposes of all keys.
As another alternative, additional functions can be added to existing keys. For example, many keyboards are configured so that certain keys generate a first signal if a key is pressed in isolation and another signal if the key is pressed in combination with a “modifier” key (e.g., the CTRL, ALT or SHIFT keys). Although it is possible to add additional modifier keys so as to assign even more possible functions to existing keys, this also has practical limits. Users are unlikely to remember all functions corresponding to all possible key combinations, and software developers are often unlikely to uniformly assign the same function to a particular key combination.
Force-sensing keys offer an advantageous way to increase the amount of data that a user can input with a computer keyboard. In most existing keyboards, a given key can only have two states; the key is either pressed (i.e., it is “down”) or it is not pressed (i.e., it is “up”). Because of this, a single key can only generate two values. A force-sensing key, on the other hand, can generate (or cause the generation of) a range of values corresponding to the amount of force exerted on the key. Pressing the key lightly may generate one signal, pressing slightly harder may generate another signal, pressing even harder may generate a third signal, etc. The additional signals can then be given meanings related to a character or function assigned to the key.
A keyboard having one or more force-sensing keys presents many data processing challenges. Indeed, computer operating system software that provides a way of receiving force data from individual keys and providing that information to application software may not be available. Moreover, an operating system able to process key force data would, in all probability, also be used in combination with non-force-sensing keyboards. Accordingly, compatibility with both types of keyboards would be highly advantageous. Similarly, not all software applications may be able to use the additional data provided by a force-sensing keyboard, and key force data should be processed in a manner compatible with applications that do not use key force data.